Aim: What are some of Earth

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Aim What are some of Earths wind patterns?
I. Winds and Pressure Belts
A. Convection cell when air circulates by
rising in one place and sinking at another.
1. Convection cells occur because cooler, more
dense air sinks toward the earths surface,
pulled by earths gravity, causing the warmer,
less dense air to rise.
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B. Pressure belts are produced due to convection.
1. Low pressure belts are found at the equator
and 60oN and S latitudes.
a. Air rises and converges. Thus, called zones
of convergence.
2. High Pressure Belts are found at the poles and
30o N and S latitudes.
a. Air descends and diverges. Known as zones of
divergence.
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High and Low Pressure Centers
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C. Coriolis Effect rotation of earth causes
winds to deflect.
1. In the northern hemisphere, winds are
deflected to the right.
2. In the southern hemisphere, winds are
deflected to the left.
GAME
3. Winds are a result of air moving from regions
of divergence (high pressure) to areas of
convergence (low pressure).
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D. Trade Winds winds flowing toward the equator
between 30o and 0o in both hemispheres. (NE and
SE trades)
1. Doldrums where trade winds of N S
hemispheres meet at the equator. Very weak winds
in this area.
E. Westerlies winds located between 30-60o in
North and Southern hemispheres.
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F. Jet Streams occur high in the troposphere
and low in the stratosphere.
1. Due to great difference in air temperature.
Why do great differences in air temperature cause
high speed winds?
2. These winds are found at an altitude of 10-15
km, are about 100 km wide, and are 2-3 km thick.
These winds may reach a speed of 500 km per
hour!!!!
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G. Local winds not part of the global wind
belts.
1. Breeze gentle wind that extends over
distance of less than 100 km.
a. Sea breeze occurs during the day. when air
over the water blows towards the land due to
temperature and pressure differences.
b. Land breeze - occurs at night. When air over
the land moves towards the water due to
temperature and pressure differences.